Subtract 72/18 from 20/40
1st number: 20/40, 2nd number: 4 0/18
20/40 - 72/18 is -7/2.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 40 and 18 is 360
Next, find the equivalent fraction of both fractional numbers with denominator 360 - For the 1st fraction, since 40 × 9 = 360,
20/40 = 20 × 9/40 × 9 = 180/360 - Likewise, for the 2nd fraction, since 18 × 20 = 360,
72/18 = 72 × 20/18 × 20 = 1440/360 - Subtract the two like fractions:
180/360 - 1440/360 = 180 - 1440/360 = -1260/360 - After reducing the fraction, the answer is -7/2
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 20/80-72/18 20/40-72/36 60/40-72/18 20/40-72/54 20/40-72/90